Digital cameras have become one of the most indispensable tools in our daily life along with the development and widespread thereof. Unlike the conventional film cameras, digital cameras can be used for continuously capturing images. Besides, images captured by a digital camera can be viewed in real time so that they can be deleted any time. Generally speaking, images captured by using a digital camera (especially those of children) may not be satisfactory. As to children, their many expressions (smiling, crying, or even grimace) are all precious memories to their parents. Accordingly, a user usually takes several continuous images at one time and then selects the most satisfactory image from all the captured images.
However, it is very time-consuming and troublesome to the user to select images, and people tend to feel uneasy in front of digital cameras. Thus, it is very difficult to capture good images with vivid facial expressions. Parents also have difficulty to take care of children and take pictures at the same time. Besides, children tend to show their true feelings when faced with toys (especially interactive toys) but limited expressions when faced with cameras and instructions of adults.